Re: SQL3 UNDER
От | Chris Bitmead |
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Тема | Re: SQL3 UNDER |
Дата | |
Msg-id | 392A4C88.FC236C09@bitmead.com обсуждение исходный текст |
Ответ на | SQL3 UNDER (Chris Bitmead <chris@bitmead.com>) |
Ответы |
Re: SQL3 UNDER
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Список | pgsql-hackers |
> I'll try to provide examples later. For now, did you see the gif > attachments on a earlier message of mine? I didn't before, but I do now. > The UNDER and CLONES/INHERITS gif pictures > provide a graphical view of what I mean. UNDER creates tree hierarchy > down vertically, while INHERITS supports multiple inheritance in a > lateral direction. The UNDER trees can be under any table that is part > of an INHERITS relationship. UNDER and INHERITS work at different > levels sorta. A subtable in an UNDER hierarchy can't be in an INHERITS > clause because it is logically just part of itsmaximal supertable. In > other words, INHERITS can provide a relationship between different > whole trees created by UNDER, by way of a maximal supertable being > inherited by another maximal supertable with its own > UNDER tree. Make any sense? :-) I'm afraid not. Show me the (SQL) code :-).
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